A bacterial strain, designated NS31-3T, was isolated from the wastewater of a paper mill. Cells of the isolate were obligately anaerobic, non-pigmented, non-motile, Gram-negative, short rods (0.7–1.0×1.4–2.5 µm). The isolate was able to grow on media containing 20 % bile salts. API 20A tests showed that acid was produced from glucose, lactose, sucrose, maltose, d-xylose, l-arabinose, cellobiose, d-mannose, d-melezitose, d-raffinose, d-trehalose, d-mannitol, salicin and d-sorbitol. The main fermentation products from PYG broth were lactic acid, propionic acid, formic acid and acetic acid. Chemotaxonomic analysis showed that the major fatty acids were anteiso-C15 : 0, C15 : 0 and iso-C17 : 0 3-OH and the predominant respiratory quinones were MK-9 and MK-10. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain NS31-3T was related to members of genus Parabacteroides (91.2–93.2 % sequence similarity); the isolate had the closest affinity with Parabacteroides merdae JCM 9497T. The G+C content of the genomic DNA was 37.2 mol%. On the basis of phenotypic, chemotaxonomic and phylogenetic analysis, strain NS31-3T represents a novel species of the genus Parabacteroides , for which the name Parabacteroides chartae sp. nov. is proposed. The type strain is NS31-3T ( = JCM 17797T = DSM 24967T).

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Parabacteroides chartae sp. nov., an obligately anaerobic species from wastewater of a paper mill.

The members of the phylum Bacteroidetes are recognized as some of the most important specialists for the degradation of polysaccharides. However, in contrast to research on Bacteroidetes in the human gut, research on polysaccharide degradation by marine Bacteroidetes is still rare. The genus Algibacter belongs to the Flavobacteriaceae family of the Bacteroidetes, and most species in this genus are isolated from or near the habitat of algae, indicating a preference for the complex polysaccharides of algae. In this work, a novel brown-seaweed-degrading strain designated HZ22 was isolated from the surface of a brown seaweed (Laminaria japonica). On the basis of its physiological, chemotaxonomic, and genotypic characteristics, it is proposed that strain HZ22 represents a novel species in the genus Algibacter with the proposed name Algibacter alginolytica sp. nov. The genome of strain HZ22, the type strain of this species, harbors 3,371 coding sequences (CDSs) and 255 carbohydrate-active enzymes (CAZymes), including 104 glycoside hydrolases (GHs) and 18 polysaccharide lyases (PLs); this appears to be the highest proportion of CAZymes (∼7.5%) among the reported strains in the class Flavobacteria Seventeen polysaccharide utilization loci (PUL) are predicted to be specific for marine polysaccharides, especially algal polysaccharides from red, green, and brown seaweeds. In particular, PUL N is predicted to be specific for alginate. Taking these findings together with the results of assays of crude alginate lyases, we prove that strain HZ22(T) can completely degrade alginate. This work reveals that strain HZ22(T) has good potential for the degradation of algal polysaccharides and that the structure and related mechanism of PUL in strain HZ22(T) are worth further research.

Isolation and Complete Genome Sequence of Algibacter alginolytica sp. nov., a Novel Seaweed-Degrading Bacteroidetes Bacterium with Diverse Putative Polysaccharide Utilization Loci

Two Gram-negative, motile, aerobic bacterial strains, designated B2T and 1_C16_27T, were respectively isolated from a seawater sample collected from the East China Sea and a semi-coke sample from north-eastern Estonia. Their genetic, phenotypic and chemotaxonomic properties were studied. The isolates were short rods with polar flagella and were positive for catalase and oxidase activities. Q-10 was the predominant respiratory ubiquinone. The major polar lipids were phosphatidylglycerol, diphosphatidylglycerol and two unidentified glycolipids. The major fatty acids were nonadecanoic (C19 : 0 cyclo), octadecanoic (C18 : 0 and C18 : 0 3-OH), octadecenoic (C18 : 1) and hexadecanoic (C16 : 0) acids. The G+C content of the genomic DNA was 58.1–59.3 mol%. 16S rRNA gene sequence analysis revealed that the two isolates represent a distinct lineage within the family Hyphomicrobiaceae. The phylogenetically closest relatives were Cucumibacter (92.7–93.7 % 16S rRNA gene sequence similarity), Devosia (92.9–94.4 %) and Zhangella (91.7–92.1 %). Differential phenotypic properties, together with phylogenetic and genetic distinctiveness, revealed that strains B2T and 1_C16_27T could be differentiated from each other and from members of the genera Cucumibacter, Devosia and Zhangella. Therefore, it is proposed that strains B2T and 1_C16_27T represent two novel species in a new genus, for which the names Pelagibacterium halotolerans gen. nov., sp. nov. (the type species; type strain B2T  = CGMCC 1.7692T  = JCM 15775T) and Pelagibacterium luteolum sp. nov. (type strain 1_C16_27T  = CGMCC 1.10267T  = JCM 16552T  = CELMS EEUT 1C1627T) are proposed.

Pelagibacterium halotolerans gen. nov., sp. nov. and Pelagibacterium luteolum sp. nov., novel members of the family Hyphomicrobiaceae.

Taxonomy of Halophiles

A phylogenetic study of the family Halomonadaceae was carried out based on complete 16S rRNA and 23S rRNA gene sequences. Several 16S rRNA genes of type strains were resequenced, and 28 new sequences of the 23S rRNA gene were obtained. Currently, the family includes nine genera (Carnimonas, Chromohalobacter, Cobetia, Halomonas, Halotalea, Kushneria, Modicisalibacter, Salinicola and Zymobacter). These genera are phylogenetically coherent except Halomonas, which is polyphyletic. This genus comprises two clearly distinguished clusters: group 1 includes Halomonas elongata (the type species) and the species Halomonas eurihalina, H. caseinilytica, H. halmophila, H. sabkhae, H. almeriensis, H. halophila, H. salina, H. organivorans, H. koreensis, H. maura and H. nitroreducens. Group 2 comprises the species Halomonas aquamarina, H. meridiana, H. axialensis, H. magadiensis, H. hydrothermalis, H. alkaliphila, H. venusta, H. boliviensis, H. neptunia, H. variabilis, H. sulfidaeris, H. subterranea, H. janggokensis, H. gomseomensis, H. arcis and H. subglaciescola. Halomonas salaria forms a cluster with Chromohalobacter salarius and the recently described genus Salinicola, and their taxonomic affiliation requires further study. More than 20 Halomonas species are phylogenetically not within the core constituted by the Halomonas sensu stricto cluster (group 1) or group 2 and, since their positions on the different phylogenetic trees are not stable, they cannot be recognized as additional groups either. In general, there is excellent agreement between the phylogenies based on the two rRNA gene sequences, but the 23S rRNA gene showed higher resolution in the differentiation of species of the family Halomonadaceae.

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Phylogenetic relationships within the family Halomonadaceae based on comparative 23S and 16S rRNA gene sequence analysis.

Three strains of Gram-negative, aerobic, neutrophilic and halophilic bacteria were isolated from samples of a salt lake on the Qinghai-Tibet Plateau and a subterranean saline well in the Si-Chuan Basin of China. These isolates, designated AJ275(T), AJ282(T) and ZG16(T), were investigated using a polyphasic approach. Based on 16S rRNA gene sequence analysis, the isolates could be affiliated to the genus Halomonas. Genomic DNA G+C contents were 65.9 mol% for AJ275(T), 56.7 mol% for AJ282(T) and 57.6 mol% for ZG16(T). The results of DNA-DNA hybridizations, fatty acid analysis and physiological and biochemical tests allowed the isolates to be differentiated genotypically and phenotypically from closely related species. It is proposed that strains AJ275(T) (=CGMCC 1.6493(T)=JCM 14606(T)=LMG 23976(T)), AJ282(T) (=CGMCC 1.6494(T)=JCM 14607(T)=LMG 23978(T)) and ZG16(T) (=CGMCC 1.6495(T)=JCM 14608(T)=LMG 23977(T)) represent the type strains of three novel species in the genus Halomonas: Halomonas saccharevitans sp. nov., Halomonas arcis sp. nov. and Halomonas subterranea sp. nov., respectively.

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Halomonas saccharevitans sp. nov., Halomonas arcis sp. nov. and Halomonas subterranea sp. nov., halophilic bacteria isolated from hypersaline environments of China

Zhen Zhou

Papers

Halomonas saccharevitans sp. nov., Halomonas arcis sp. nov. and Halomonas subterranea sp. nov., halophilic bacteria isolated from hypersaline environments of China